Abstract

Simultaneous recovery of manganese and zinc from electrolyte paste of spent zinc-carbon dry cell battereis

Author(s): Majharul Haque Khan, A.S.W.Kurny

Electrolyte paste of spent zinc-carbon dry cell batteries were leached in sulfuric acid with hydrogen peroxide as a reducing agent. Effects of operating variables such as, concentration of sulfuric acid and hydrogen peroxide in the leaching solution, temperature, stirring speed and solid/liquid ratio were investigated to determine the optimumleaching conditions. Optimum leaching conditionswere identified as: concentration of sulfuric acid: 2.5M, concentration of hydrogen peroxide: 10%,Temperature: 600C, stirring speed: 600 rpm; and solid-liquid ratio 1:12. Under these conditions a maximumof 88% manganese could be dissolved from the electrolyte paste within only 27 minutes of leaching. Dissolution of zinc under the same conditions was 97%. A maximum of 83.29% of zinc could be precipitated from the leach liquor in the formof oxalate while the precipitation ofmanganese in the form carbonate was 69.89%.